Voltage regulator



NOV. 13,1945. R, PRESTON v 2,388,996

VOLTAGE REGULATOR Filed Oct. 4, 1944 2 Sheets-Sheet 1 F/G. Z

nvsua A "non! I FIG.

IN VEN TOR. EAL/ H H. PRESTO/V Nov} 13, 1945. R. H. PRESTON VOLTAGE REGULATOR 2 Sheets-Sheet 2 Filed Oct. 4, 194-4 IN V EN TOR.

@ALPH H. PRESTO/V BY 3 4 Patented Nov. 13, 1945 VOLTAGE REGULATOR Ralph 1!. Preston, Roseland, N. J., asslgnor to American Transformer Company,

Newark,

Application October 4, 1944, Serial No. 557,175

11 Claims.

Thi invention relates to a voltage regulator of the continuously variable auto-transformer type such as disclosed in Schermerhorn Patent 2,089,434, issued August 10, 1937. The regulator to be described herein is designed particularly for obtaining a variable voltage from a suitable source of alternating current supply and is especially adapted for handling a small current.

One of the objects of my invention i to provide a regulator of relatively low wattcapacity which will give exceedingly fine regulation at high efficiency.

A further object of my invention is to provide a construction in which the regulator can be quickly converted from a table mounting to a rear board or panel mounting.

Another object of my invention is to provide a regulator construction in which the contact brush is carried in a new and novel manner whereby a good contact is 'made between the brush and the arm carrying it, and in which the brush and spring may be very easily removedfrom the arm for inspection or renewal purposes.

A still further object is to provide improved, simple and cheap means of mounting the transformer core and winding on the base support.

A still further object is to provide improved means for mounting the brush arm and conveying current thereto.

These and other objects will be readily appreciated by one skilled in the art by a reading of the specification taken i connection with the annexed drawings wherein:

Figure l is a front elevational view of the complete unit.

Figure 2 is a view on the line 2-2 of Figure 1.

Figure 3 is a part-sectional and part-elevational view, taken on the line 3--3 of Figure 4, and also showing in broken lines the manner in which the regulator can be converted from a table mounting to a panel mounting.

Figure 4 is a view of the bottom of the structure.

Figure 5 is a sectional view on the line 55 of Figure 3, all of the views of Figures 1 to 5 inclusive being on a somewhat reduced scale from the operative structure.

Figure 6 is a full-size view of the contact brush spring.

Figure 7 is a diagrammatic view of the electrical circuits of the regulator, including a Table of connections.

In the various views, wherein like numbers refer to corresponding parts, 6 is a base support of strong and preferably heat-resisting insulating material, such as a thermo-setting, phenolic, ragfilled material, preferably having a plurality of bosses I for resting on a table. The base 6 ha a recess 8 from which extends a column 9 preferably moulded integrally with the base 6. The base is provided with a plurality of barriers In between which are mounted terminals numbered l to 5.

Extending upwardly from the base 6 is an annular flange ll, within the periphery of which is mounted the transformer core I2 and toroidal winding l3, it being understood that the core and winding rest on a cushioning gasket 53.

The core and winding are securely fastened within the periphery of the flange H by means of a clamp [4, preferably having some resiliency, having a plurality of arms l5, three of which are utilized as shown in Figure 2. The clamp 14 is held in place onthe column, near one end thereof, by a retaining member l6 which is preferably of the locking ring type and is snapped into position ina groove within the column 9. The ends of the arms I5 rest on an annular insulator ll positioned on the ends l8 of the regulator winding l3.

Positioned within the column 9, is a metallic sleeve or auxiliary shaft IS, on the upper end of which is pressed the hub 20 of the brush arm 2i of suitable metal which may be die-cast aluminum. Preferably the arm 2| and sleeve 49 are assembled as a unit before assembly into the regulator.

It will be noted from Figures 3 and 4, that the sleeve it extends within the recess 8 of the base, and positioned over this sleeve is a contact terminal having a circular base portion 22 of suitable material such as copper, and a finger 23 extending outwardly between bosses 49 moulded integrally with the wall of the base recess and connected to the terminal 3.

Engaging the terminal 22, is a spring washer 24 that i held under tension against the terminal 22 by means of a clamping ring 25 held in looking position by a screw and nut 26. The clamp 25 has an integrally formed arm 21 which is adapted to engage a stop 28 moulded integrally with the base 6 to stop the rotation of the brush arm 2| in the position shown in Figure l. Also fastened to the sleeve l9 and closely adjacent the clamp 25, is a second clamp 29 having a integrally formed arm 30 which is also adapted to engage the stop 28 when the brush arm is moved to its extremity in the other direction from that shown in Figure 1.

Carried within the sleeve 19, is a shaft 3i to which is fastened, as by a pin 32, the sleeve IS, the pin 32 also passing through the hub 20 of the brush arm 2|. On the upper end of the shaft 3|, is carried a calibration dial 33 and a control knob 34. The free end of the arm 2| forthe brush 3?.

winding l3 so as to expose the conductors which are wound in close relationship. The width of the brush 3'! is such that only approximately three of the small conductors are bridged simultaneously, and since the number of conductors in'this piece of apparatus is relatively large, a very small change in potential is obtained which may be on the order of /4 to l -volt.

The brush 3? has fastened thereto a pigtail as of fine stranded copper wire which is fastened to the arm 29 by a screw dd seated in a recess ii in the arm. It'will be noted from Figure 3, that the pigtail 39 is carried up to the screw 60 through a slot 52 which intercepts the oriflce 35, into which an opening 38 extends, the width of the opening 53 being in alignment with and approximately the same width as the opening These two openings extend from opposite sides of the hole 35 through the material of the arm. As a matter of fact, these rectangularly shaped openings are longer than the vertical dimension of the hole 35, thereby forming grooves or channels Ed and 55, within which the brush 3? operates in perfect alignment with the brush track 38.

It will be noted from Figures 5 and 6 that the brush spring 35 is formed in somewhat elliptical shape out of one piece of suitable fiat metal such as bronze, spring copper or beryllium copper, and has a recess 44 therein to receive the outer ed e of the brush 87, thereby aligning the spring with the brush; while the ends of the spring are formed over and interlocked at 45, and this interlocking formation enters the opening at in the end of the arm 2!. This provides a very effective and self-aligning means for applying pressure tothe brush 31, as well as a simple and quickly operative means for removing the brush for inspection or renewal purposes, for the reason that by a slight pressure on the protruding ends of the spring 6 (see Figure 1), the interlocking formation 45 may be pushed out of the opening 43 when the spring 36 is withdrawn from the orifice 35, and sincethe width of the opening 43 is slightly more than the thickness of the brush 81, the brush may be withdrawn from its opening through the opening 43 after the binding screw 40 is removed, the pigtail passing then adjacent the edge 46 of the insulating strip 41.

As shown in Figures 1 to .3, the regulator is assembled for mounting on a table and may be fastened thereto through the medium of'the mounting holes 50. When it is desired to mount the regulator on the back of a board or panel mounting, all that is necessary to be done is to remove the pin 32 and withdraw the shaft 3|,

which is provided with a hole 52, shown in dottedlines, at its opposite end, and insert it in reverse assspoe position through the panel 5|, shown in broken lines in Figure 3, and then re-insert the pin 82 through the hub 20, the arm 2! and the hole 52. after which the mounting studs may be passed through the panel and through the holes it in the base 8. While the shaft 3! may be of suitable metal, I prefer to make it of strong insulating material to absolutely prevent an operator getting an electrical shock, although the handle 86 is of insulating material. Furthermore, if the regulators are arranged in gangs for polyphase use, as shown in Figure 12 of the Schermerhorn patent previously referred to, the shaft of insulating material is necessary.

The methods of making connection to the winding of the regulator and the output voltages are given in Figure 7 and it would appear that further description seems to be. unnecessary.

What I claim is:

l. A voltage regulator including a recessed base of suitable insulating material and having an integral centrally located outwardly extending column with a groove therein near its normally free end, a circular core of suitabl magnetic material carrying a toroidal winding of closely arranged conductors, the outer turns of which have at least a'circularly bared portion to form a brush contact surface, the core and winding being seated at one end on the base around said column, clamping means engaging the opposite end of the winding and core, a retaining member carried by the groove in said column for holding said clamping means in clamping position, a cylindrical metallic sleeve or auxiliary shaft passing through said column, a brush arm securely fastened mechanically and electrically to the cylindrical sleeve at the free end of the column and extending radially from the column and downwardly at its free end over the winding, a brush resiliently carried by the free end of the arm in,

engagement with said brush contact surface on the winding, an operating shaft passing throughsaid cylindrical sleeve and removably fastened thereto adjacent the free end of the column, a stop within the recess of the base, stop means adjustably carried on the sleeve for engag g said base stop for both directions of rotation of the shaft, and terminals carried by the base for making connections to the winding and sleeve.

2. A voltage regulator including a base of suitable insulating material and having an integral centrally located outwardly extending tapered column with an annular groove near the free end thereof, a core of suitable magnetic material having a winding thereon, the outer turns of which form a cylindrical surface, at least a portion of which is bared to form a brush contact surface, the base having a recess around the foot of said column to receive one end of said core and winding, a resilient clamp for engaging the opposite ends of said .core and winding, a retaining member carried by the groove in said column for holding said clamp inclamping position, a hollow auxiliary shaft or sleeve passing through the column at both ends thereof, a brush arm securely fastened to said auxiliary shaft or sleeve at the free end of the column and extending radially from the column, a brush resiliently carried by the free end of the arm for engagement with said brush contact surface on the winding, an operating shaft passing through the auxiliary shaft or sleeve and removably attached thereto, a stop positioned in the base, stop means adjustably carried on the auxiliary shaft or sleeve for engaging said base stop for both directions of the base for making connections to the winding and auxiliary shaft or sleeve.

3. A voltage regulator as defined in claim 1,

further characterized in that the base is provided with an annular ring, a portion of which is divided by barriers into separate compartments for receiving the termina1s for making connections to the winding, electrical connection bein made to the auxiliary shaft or sleeve by a terminal fitting over the auxiliaryshaft orsleeve against the base of the column, with a spring washer firmly pressed against said member by said stop means carried by the auxiliary shaft brush 'positipned in one of said openings and having contact means with the arm, a spring extending through said hole and having a seatflon the brush and a formation extending into the other of said openings for holding the spring in operative. position in the arm and against the 8. In an electrical regulator having a core and winding with a part of the winding hated to form a brush-trackmg surface, an operating shait carrying a brush arm with means for conveying current to said am, said arm having a transverse hole through its free end with openings at right angles thereto to opposite sides of the arm end, a brush positioned in one of said openings and having contact means with the arm, a spring formed from a, single piece of flat metal into a closed elliptically shaped loop having a seat for the brush on one side of its long axis and an interlocking formation of its ends on the opposite side from the brush seat, the spring being positioned in the transverse hole with the said formation located in the outer of said openings into said hole, while said seat holds the spring in aligning position.

or sleeve. 1 9. In an electrical regulator having a core and 4- A v a e regulator as defined in cl i 1, winding with a part of the winding bared to form further characterized in that the operating shaft brush-tracking surface, an operating shaft caris provided with means near its opposite ends rying a brush arm with means for conveying cur- Wh e y it may be fastened to the auxiliary Shaft rent to said arm, said arm having a transverse or sleeve and r h holder w n inserted f hole through its free end with Openings at right Operation from either/end 0f the 199119-1501, angles thereto to opposite sides of the arm end, a thereby providing for horizontal or vertical brush positioned i n of sai openings and havmounting. ing contact means with the arm, a spring formed 5. A voltage regulator including a hollow base from a single piece of flat metal into a closed ellipf ta l insulating material having an p- 2 tically shaped loop having a seat for the brush on wardly extending annular flange and a centrally one side r it long axis and an interlocking forlocated upwardly extending column, a unit core ati f it e d on the opposite side from the of suitable magnetic materiel an a i di brush seat, the spring being positioned in the thereon with a brush track on the winding, th transverse hole with the said formation located core and winding unit having one end seated in the outer of said openings into said hole, while within saidannular flange, mean carried by said seat holds the spring in aligning position, the l the column for engaging the opposite end of ends of the sprin 0p projecting beyond the i i the core and winding unit t0 hOld the unit seedges of the arm end whereby pressure on thesel i curely within the flange, a hollow auxiliary shaft 1 d 111 force id formation on the spring or sleeve passing through the column at both t f it position in its arm opening so the spring ends thereof, a brush arm securely fastenedsto may be readily ithdrawn from the hole in the i said sleeve at the free end of the column and extending radially from the column, a brush r 10, In an electrical regulator having a core and siliently carried by the free end of the arm for winding with a part of the winding bared to form engagement with said brush track on the wind- 40 brush t1'ack1ng urface, an operating shaft h Pemtihg shaft passing thmugh said rying a brush arm with means for conveying cursleeve and Pmvided with means whereby the rentto said arm, said arm having a transverse crating shaft can be readily connected and dishole through its free end with openings at right connected from the sleeve and arm and reversed angles thereto t opposite sides of the arm end, a in Positmh in the sleeve the regulator may he brush positioned in one of said openings and havmounted on a table or on a switchboard or panel, v Contact means t t a a spring formed means within the ho w base carried on e sai from a single piece of flat metal into a closed ellip- Sleeve and empemtme with means on t base tioally shaped loop having a seat for the brush on for stopping the rotation of the operatm Shaft one side of its long axis and an interlocking forand brush arm in both directions of rotation, and mation f its d on t pposite side from the terminals carried by the base for making connecbrush t th spring being positioned in the h to the winding and said sleeve' transverse hole with the said formation located in 6. A voltage regulator as set forth in claim 5, e outer of said openings into said hole, while further defined that the column is tapered upsaid seat holds th spring in aligning osition, the wardly and provided with means for carrying a ends f thespring 100p projegting beyond th retaining member for holding Sam means that edges of the arm end whereby pressure on these engages 9 core and winding unit to had the loop ends will force said formation on the sprin same in place withm h flange 0f the base out of its position in its arm opening so the spring In an electrical regulatm' having a core and may be readily. withdrawn from the hole in the winding with a part of the winding bared to form the arm end having a recess for a binding brush-tracking surface, an operating shah; and contact screw above the location of the brush. a brush arm with means conveying with a slot extending downwardly from the recess rentto said arm, said arm having a transverse 4 t t i g for the said spring formation hole through its free end with openings at right and transverse hole to forma passageway for angles thereto to opposite sides of the arm end, a teufrom the brush to the recess and screw therein,' the last-mentioned opening having a width so the brush. may be withdrawn therethrough after the spring is removed.

'11. An electrical regulator as defined in claim 10, further characterized in that said open gs are rectangular in shape and extend in the material of the arm beyond the vertical dimension of the spring hole, thereby forming grooves to function with the brush;

' RALPH H. PRESTON. 

